1. Field of the Invention
This invention relates to a transmission apparatus, a transmission method, a reception apparatus, a reception method and a signal transmission system which can be suitably applied to a case in which an image signal with regard to which the pixel number of one frame exceeds the number of pixels prescribed by the HD-SDI format is serially transmitted.
2. Description of the Related Art
Development of a reception system or an image pickup system for a very high definition image signal which exceeds a high definition (HD) signal which is an existing image signal or video signal with regard to which one frame has 1,920 samples×1,080 lines is proceeding. For example, a UHDTV (Ultra High Definition TV) standard which is a broadcasting system of a next generation having a number of pixels equal to four times or 16 times that of the existing HD is being standardized by international associations. The international associations include the ITU (International Telecommunication Union) and the SMPTE (Society of Motion Picture and Television Engineers).
The image standard proposed by the ITU or the SMPTE relates to an image signal having a sample number and a line number equal to twice or four times those of 1,920 samples×1,080 lines, that is, having 3,840 samples×2,160 lines or 7,680 samples×4,320 lines. That one of the image signals which is standardized by the ITU is called LSDI (Large Screen Digital Imagery) while that one which is proposed by the SMPTE is called UHDTV. As regards the UHDTV, signals of the following table 1 are prescribed.
TABLE 1Luminance or R′EffectiveG′ B′ samplelineFrameSystemnumber pernumberratecategorySystem nameeffective lineper frame(Hz)UHDTV13840 × 2160/50/P38402160503840 × 2160/59.94/P3840216060/1.0013840 × 2160/60/P3840216060UHDTV27680 × 4320/50/P76804320507680 × 4320/59.94/P7680432060/1.0017680 × 4320/60/P7680432060
Then, upon product development directed to 3840×2160/60 P, products at an initial stage are estimated as image apparatus compatible with 3840×2160/24 P, 25 P and 30 P. In addition, it is desired to supply products ready for such a frame rate other than 30 P such as 24 P by looking for an application which can utilize various 4k images.
As an interface for them, a transmission standard known as mode D is added to the SMPTE 435-2, and standardization is completed as SMPTE 435-2-2009. On the basis of this system, according to the UHDTV standard, a system wherein 3840×2160/60 P transmits a signal of 10 Gbps by two channels and 7680/60 P transmits a signal of 10 Gbps by eight channels is proposed as SMPTE 2036-3 by the SMPTE.
While 3840×2160/60 P is an image signal which an image producing person in a broadcasting station or the like intends to transmit, a cinema producing person in the world of cinema wants that a 2048×1080 signal or a 4096×2160 signal can be transmitted in order to transmit an image signal in a cinema region. To this end, the DCDM (Digital Cinema Distribution Master), D-cinema AFR (Additional Frame Rate), cinematography production image format is proposed by the SMPTE. Table 2 below indicates standards of a 4096×2160 signal proposed by the SMPTE as examples of a configuration of a pixel sample in the cinema region (such pixel sample may be hereinafter referred to merely as “pixel” or “sample”) and a frame rate.
TABLE 2SystemFrame rateNo.System name(Hz)14096 × 2160/60/P6024096 × 2160/59.94/P60/1.00134096 × 2160/50/P5044096 × 2160/48/P4854096 × 2160/47.95/P48/1.00164096 × 2160/30/P3074096 × 2160/29.97/P30/1.00184096 × 2160/25/P2594096 × 2160/24/P24104096 × 2160/23.98/P24/1.001
Incidentally, the SMPTE 435-2 describes mapping of data of HD-SDIs which are parallel streams of 10 bits prescribed by the SMPTE 292 to a serial interface of 10.692 Gbps. Usually, an HD-SDI is configured from fields of EAV, horizontal auxiliary data space (HANG data, also called horizontal blanking period), SAV and image data disposed in this order.
Here, examples of a method of multiplexing data included in an HD-SDI of a plurality of channels are described with reference to FIGS. 25 and 26. The methods of multiplexing data are prescribed as mode B and mode D in the SMPTE 435-2.
FIG. 25 illustrates the method of the mode B.
The mode B is a method of multiplexing data into HD-SDIs of six channels CH1 to CH6.
In the mode B, data are multiplexed in the image data region and the horizontal auxiliary data space of a 10.692 Gbps stream. The image/EAV/SAV data of 4 words included in the HD-SDI of six channels CH1 to CH6 are subjected to 8B/10B conversion so that they are encoded into a data block of 5 words or 50 bits. Then, the data block is multiplexed into the image data region of the 10.692 Gbps stream in the order of the channels beginning with the top of the SAV.
Meanwhile, the horizontal auxiliary data spaces of the HD-SDI of the four channels CH1 to CH4 are subjected to 8B/10B conversion so that they are encoded into a data block of 50 bits and multiplexed into the horizontal auxiliary data space of the 10.692 Gbps stream in the order of the channels. It is to be noted, however, the horizontal auxiliary data spaces of the HD-SDI of the channels CH5 and CH6 are not transmitted.
FIG. 26 illustrates the method of the mode D.
The mode D is a method of multiplexing HD-SDIs of eight channels CH1 to CH8.
In the mode D, data are multiplexed into the image data region and the horizontal auxiliary data space of a 10.692 Gbps stream. At this time, the image/EAV/SAV data of the HD-SDIs of the channels CH1, CH3, CH5 and CH7 are extracted by 40 bits and scrambled so as to be converted into data of 40 bits. Meanwhile, the image/EAV/SAV data of the HD-SDIs of the channels CH2, CH4, CH6 and CH8 are extracted by 32 bits and converted into data of 40 bits by 8B/10B conversion. The data are added to each other to form data of 80 bits. The encoded 8-word or 80-bit data is multiplexed into the image data region of the 10.692 Gbps stream.
At this time, to the front half data block of 40 bits from within the data block of 80 bits, the data block of 40 bits of the even-numbered channels obtained by the 8B/10B conversion is allocated. Then, to the rear half data block of 40 bits, the data block of scrambled 40 bits of the odd-numbered channels is allocated. Therefore, in the one data block, for example, the data blocks are multiplexed in the order of, for example, the channels CH2 and CH1. The reason why the order is changed in this manner is that a content ID for identifying a mode to be used is included in the data block of 40 bits of the even-numbered channels obtained by the 8B/10B conversion.
Meanwhile, the horizontal auxiliary data space of the HD-SDI of the channel CH1 is subjected to 8B/10B conversion and encoded into a data block of 50 bits. Then, the data block is multiplexed into the horizontal auxiliary data space of the 10.692 Gbps stream. It is to be noted that the horizontal auxiliary data spaces of the HD-SDI of the channels CH2 to CH8 are not transmitted.
Meanwhile, Japanese Patent Laid-Open No. 2005-328494 discloses a technique for transmitting a 3840×2160/30 P, 30/1.001 P/4:4:4/12-bit signal, which is a kind of a 4k×2k signal which is a very high resolution signal of 4k samples×2k lines at a bit rate higher than 10 Gbps. It is to be noted that the term “3840×2160/30 P” indicates a “pixel number in the horizontal direction”×“line number in the vertical direction”/“frame number per one second.” Further, “4:4:4” represents the ratio of a “red signal R:green signal G:blue signal B” in the case of the primary color signal transmission method or the ratio of a “luminance signal Y:first color difference signal Cb:second color difference signal Cr” in the case of the color difference signal transmission method.